diff options
Diffstat (limited to 'lib/Transforms/Utils/SimplifyCFG.cpp')
| -rw-r--r-- | lib/Transforms/Utils/SimplifyCFG.cpp | 600 |
1 files changed, 338 insertions, 262 deletions
diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp index 92fd56a..3248a83 100644 --- a/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/lib/Transforms/Utils/SimplifyCFG.cpp @@ -53,9 +53,13 @@ using namespace PatternMatch; #define DEBUG_TYPE "simplifycfg" +// Chosen as 2 so as to be cheap, but still to have enough power to fold +// a select, so the "clamp" idiom (of a min followed by a max) will be caught. +// To catch this, we need to fold a compare and a select, hence '2' being the +// minimum reasonable default. static cl::opt<unsigned> -PHINodeFoldingThreshold("phi-node-folding-threshold", cl::Hidden, cl::init(1), - cl::desc("Control the amount of phi node folding to perform (default = 1)")); +PHINodeFoldingThreshold("phi-node-folding-threshold", cl::Hidden, cl::init(2), + cl::desc("Control the amount of phi node folding to perform (default = 2)")); static cl::opt<bool> DupRet("simplifycfg-dup-ret", cl::Hidden, cl::init(false), @@ -73,6 +77,7 @@ STATISTIC(NumBitMaps, "Number of switch instructions turned into bitmaps"); STATISTIC(NumLinearMaps, "Number of switch instructions turned into linear mapping"); STATISTIC(NumLookupTables, "Number of switch instructions turned into lookup tables"); STATISTIC(NumLookupTablesHoles, "Number of switch instructions turned into lookup tables (holes checked)"); +STATISTIC(NumTableCmpReuses, "Number of reused switch table lookup compares"); STATISTIC(NumSinkCommons, "Number of common instructions sunk down to the end block"); STATISTIC(NumSpeculations, "Number of speculative executed instructions"); @@ -107,7 +112,7 @@ class SimplifyCFGOpt { const TargetTransformInfo &TTI; unsigned BonusInstThreshold; const DataLayout *const DL; - AssumptionTracker *AT; + AssumptionCache *AC; Value *isValueEqualityComparison(TerminatorInst *TI); BasicBlock *GetValueEqualityComparisonCases(TerminatorInst *TI, std::vector<ValueEqualityComparisonCase> &Cases); @@ -127,8 +132,8 @@ class SimplifyCFGOpt { public: SimplifyCFGOpt(const TargetTransformInfo &TTI, unsigned BonusInstThreshold, - const DataLayout *DL, AssumptionTracker *AT) - : TTI(TTI), BonusInstThreshold(BonusInstThreshold), DL(DL), AT(AT) {} + const DataLayout *DL, AssumptionCache *AC) + : TTI(TTI), BonusInstThreshold(BonusInstThreshold), DL(DL), AC(AC) {} bool run(BasicBlock *BB); }; } @@ -215,45 +220,15 @@ static void AddPredecessorToBlock(BasicBlock *Succ, BasicBlock *NewPred, } /// ComputeSpeculationCost - Compute an abstract "cost" of speculating the -/// given instruction, which is assumed to be safe to speculate. 1 means -/// cheap, 2 means less cheap, and UINT_MAX means prohibitively expensive. -static unsigned ComputeSpeculationCost(const User *I, const DataLayout *DL) { +/// given instruction, which is assumed to be safe to speculate. TCC_Free means +/// cheap, TCC_Basic means less cheap, and TCC_Expensive means prohibitively +/// expensive. +static unsigned ComputeSpeculationCost(const User *I, const DataLayout *DL, + const TargetTransformInfo &TTI) { assert(isSafeToSpeculativelyExecute(I, DL) && "Instruction is not safe to speculatively execute!"); - switch (Operator::getOpcode(I)) { - default: - // In doubt, be conservative. - return UINT_MAX; - case Instruction::GetElementPtr: - // GEPs are cheap if all indices are constant. - if (!cast<GEPOperator>(I)->hasAllConstantIndices()) - return UINT_MAX; - return 1; - case Instruction::ExtractValue: - case Instruction::Load: - case Instruction::Add: - case Instruction::Sub: - case Instruction::And: - case Instruction::Or: - case Instruction::Xor: - case Instruction::Shl: - case Instruction::LShr: - case Instruction::AShr: - case Instruction::ICmp: - case Instruction::Trunc: - case Instruction::ZExt: - case Instruction::SExt: - case Instruction::BitCast: - case Instruction::ExtractElement: - case Instruction::InsertElement: - return 1; // These are all cheap. - - case Instruction::Call: - case Instruction::Select: - return 2; - } + return TTI.getUserCost(I); } - /// DominatesMergePoint - If we have a merge point of an "if condition" as /// accepted above, return true if the specified value dominates the block. We /// don't handle the true generality of domination here, just a special case @@ -274,7 +249,8 @@ static unsigned ComputeSpeculationCost(const User *I, const DataLayout *DL) { static bool DominatesMergePoint(Value *V, BasicBlock *BB, SmallPtrSetImpl<Instruction*> *AggressiveInsts, unsigned &CostRemaining, - const DataLayout *DL) { + const DataLayout *DL, + const TargetTransformInfo &TTI) { Instruction *I = dyn_cast<Instruction>(V); if (!I) { // Non-instructions all dominate instructions, but not all constantexprs @@ -310,7 +286,7 @@ static bool DominatesMergePoint(Value *V, BasicBlock *BB, if (!isSafeToSpeculativelyExecute(I, DL)) return false; - unsigned Cost = ComputeSpeculationCost(I, DL); + unsigned Cost = ComputeSpeculationCost(I, DL, TTI); if (Cost > CostRemaining) return false; @@ -320,7 +296,7 @@ static bool DominatesMergePoint(Value *V, BasicBlock *BB, // Okay, we can only really hoist these out if their operands do // not take us over the cost threshold. for (User::op_iterator i = I->op_begin(), e = I->op_end(); i != e; ++i) - if (!DominatesMergePoint(*i, BB, AggressiveInsts, CostRemaining, DL)) + if (!DominatesMergePoint(*i, BB, AggressiveInsts, CostRemaining, DL, TTI)) return false; // Okay, it's safe to do this! Remember this instruction. AggressiveInsts->insert(I); @@ -383,10 +359,9 @@ struct ConstantComparesGatherer { } /// Prevent copy - ConstantComparesGatherer(const ConstantComparesGatherer &) - LLVM_DELETED_FUNCTION; + ConstantComparesGatherer(const ConstantComparesGatherer &) = delete; ConstantComparesGatherer & - operator=(const ConstantComparesGatherer &) LLVM_DELETED_FUNCTION; + operator=(const ConstantComparesGatherer &) = delete; private: @@ -712,8 +687,7 @@ SimplifyEqualityComparisonWithOnlyPredecessor(TerminatorInst *TI, if (HasWeight) for (unsigned MD_i = 1, MD_e = MD->getNumOperands(); MD_i < MD_e; ++MD_i) { - ConstantInt* CI = dyn_cast<ConstantInt>(MD->getOperand(MD_i)); - assert(CI); + ConstantInt *CI = mdconst::extract<ConstantInt>(MD->getOperand(MD_i)); Weights.push_back(CI->getValue().getZExtValue()); } for (SwitchInst::CaseIt i = SI->case_end(), e = SI->case_begin(); i != e;) { @@ -818,7 +792,7 @@ static void GetBranchWeights(TerminatorInst *TI, MDNode *MD = TI->getMetadata(LLVMContext::MD_prof); assert(MD); for (unsigned i = 1, e = MD->getNumOperands(); i < e; ++i) { - ConstantInt *CI = cast<ConstantInt>(MD->getOperand(i)); + ConstantInt *CI = mdconst::extract<ConstantInt>(MD->getOperand(i)); Weights.push_back(CI->getValue().getZExtValue()); } @@ -1079,7 +1053,8 @@ static bool passingValueIsAlwaysUndefined(Value *V, Instruction *I); /// HoistThenElseCodeToIf - Given a conditional branch that goes to BB1 and /// BB2, hoist any common code in the two blocks up into the branch block. The /// caller of this function guarantees that BI's block dominates BB1 and BB2. -static bool HoistThenElseCodeToIf(BranchInst *BI, const DataLayout *DL) { +static bool HoistThenElseCodeToIf(BranchInst *BI, const DataLayout *DL, + const TargetTransformInfo &TTI) { // This does very trivial matching, with limited scanning, to find identical // instructions in the two blocks. In particular, we don't want to get into // O(M*N) situations here where M and N are the sizes of BB1 and BB2. As @@ -1114,6 +1089,9 @@ static bool HoistThenElseCodeToIf(BranchInst *BI, const DataLayout *DL) { if (isa<TerminatorInst>(I1)) goto HoistTerminator; + if (!TTI.isProfitableToHoist(I1) || !TTI.isProfitableToHoist(I2)) + return Changed; + // For a normal instruction, we just move one to right before the branch, // then replace all uses of the other with the first. Finally, we remove // the now redundant second instruction. @@ -1244,14 +1222,13 @@ static bool SinkThenElseCodeToEnd(BranchInst *BI1) { return false; // Gather the PHI nodes in BBEnd. - std::map<Value*, std::pair<Value*, PHINode*> > MapValueFromBB1ToBB2; + SmallDenseMap<std::pair<Value *, Value *>, PHINode *> JointValueMap; Instruction *FirstNonPhiInBBEnd = nullptr; - for (BasicBlock::iterator I = BBEnd->begin(), E = BBEnd->end(); - I != E; ++I) { + for (BasicBlock::iterator I = BBEnd->begin(), E = BBEnd->end(); I != E; ++I) { if (PHINode *PN = dyn_cast<PHINode>(I)) { Value *BB1V = PN->getIncomingValueForBlock(BB1); Value *BB2V = PN->getIncomingValueForBlock(BB2); - MapValueFromBB1ToBB2[BB1V] = std::make_pair(BB2V, PN); + JointValueMap[std::make_pair(BB1V, BB2V)] = PN; } else { FirstNonPhiInBBEnd = &*I; break; @@ -1260,13 +1237,13 @@ static bool SinkThenElseCodeToEnd(BranchInst *BI1) { if (!FirstNonPhiInBBEnd) return false; - // This does very trivial matching, with limited scanning, to find identical // instructions in the two blocks. We scan backward for obviously identical // instructions in an identical order. BasicBlock::InstListType::reverse_iterator RI1 = BB1->getInstList().rbegin(), - RE1 = BB1->getInstList().rend(), RI2 = BB2->getInstList().rbegin(), - RE2 = BB2->getInstList().rend(); + RE1 = BB1->getInstList().rend(), + RI2 = BB2->getInstList().rbegin(), + RE2 = BB2->getInstList().rend(); // Skip debug info. while (RI1 != RE1 && isa<DbgInfoIntrinsic>(&*RI1)) ++RI1; if (RI1 == RE1) @@ -1289,6 +1266,7 @@ static bool SinkThenElseCodeToEnd(BranchInst *BI1) { return Changed; Instruction *I1 = &*RI1, *I2 = &*RI2; + auto InstPair = std::make_pair(I1, I2); // I1 and I2 should have a single use in the same PHI node, and they // perform the same operation. // Cannot move control-flow-involving, volatile loads, vaarg, etc. @@ -1299,11 +1277,11 @@ static bool SinkThenElseCodeToEnd(BranchInst *BI1) { I1->mayHaveSideEffects() || I2->mayHaveSideEffects() || I1->mayReadOrWriteMemory() || I2->mayReadOrWriteMemory() || !I1->hasOneUse() || !I2->hasOneUse() || - MapValueFromBB1ToBB2.find(I1) == MapValueFromBB1ToBB2.end() || - MapValueFromBB1ToBB2[I1].first != I2) + !JointValueMap.count(InstPair)) return Changed; // Check whether we should swap the operands of ICmpInst. + // TODO: Add support of communativity. ICmpInst *ICmp1 = dyn_cast<ICmpInst>(I1), *ICmp2 = dyn_cast<ICmpInst>(I2); bool SwapOpnds = false; if (ICmp1 && ICmp2 && @@ -1324,16 +1302,13 @@ static bool SinkThenElseCodeToEnd(BranchInst *BI1) { // with a PHI node after sinking. We only handle the case where there is // a single pair of different operands. Value *DifferentOp1 = nullptr, *DifferentOp2 = nullptr; - unsigned Op1Idx = 0; + unsigned Op1Idx = ~0U; for (unsigned I = 0, E = I1->getNumOperands(); I != E; ++I) { if (I1->getOperand(I) == I2->getOperand(I)) continue; - // Early exit if we have more-than one pair of different operands or - // the different operand is already in MapValueFromBB1ToBB2. - // Early exit if we need a PHI node to replace a constant. - if (DifferentOp1 || - MapValueFromBB1ToBB2.find(I1->getOperand(I)) != - MapValueFromBB1ToBB2.end() || + // Early exit if we have more-than one pair of different operands or if + // we need a PHI node to replace a constant. + if (Op1Idx != ~0U || isa<Constant>(I1->getOperand(I)) || isa<Constant>(I2->getOperand(I))) { // If we can't sink the instructions, undo the swapping. @@ -1346,24 +1321,27 @@ static bool SinkThenElseCodeToEnd(BranchInst *BI1) { DifferentOp2 = I2->getOperand(I); } - // We insert the pair of different operands to MapValueFromBB1ToBB2 and - // remove (I1, I2) from MapValueFromBB1ToBB2. - if (DifferentOp1) { - PHINode *NewPN = PHINode::Create(DifferentOp1->getType(), 2, - DifferentOp1->getName() + ".sink", - BBEnd->begin()); - MapValueFromBB1ToBB2[DifferentOp1] = std::make_pair(DifferentOp2, NewPN); + DEBUG(dbgs() << "SINK common instructions " << *I1 << "\n"); + DEBUG(dbgs() << " " << *I2 << "\n"); + + // We insert the pair of different operands to JointValueMap and + // remove (I1, I2) from JointValueMap. + if (Op1Idx != ~0U) { + auto &NewPN = JointValueMap[std::make_pair(DifferentOp1, DifferentOp2)]; + if (!NewPN) { + NewPN = + PHINode::Create(DifferentOp1->getType(), 2, + DifferentOp1->getName() + ".sink", BBEnd->begin()); + NewPN->addIncoming(DifferentOp1, BB1); + NewPN->addIncoming(DifferentOp2, BB2); + DEBUG(dbgs() << "Create PHI node " << *NewPN << "\n";); + } // I1 should use NewPN instead of DifferentOp1. I1->setOperand(Op1Idx, NewPN); - NewPN->addIncoming(DifferentOp1, BB1); - NewPN->addIncoming(DifferentOp2, BB2); - DEBUG(dbgs() << "Create PHI node " << *NewPN << "\n";); } - PHINode *OldPN = MapValueFromBB1ToBB2[I1].second; - MapValueFromBB1ToBB2.erase(I1); + PHINode *OldPN = JointValueMap[InstPair]; + JointValueMap.erase(InstPair); - DEBUG(dbgs() << "SINK common instructions " << *I1 << "\n";); - DEBUG(dbgs() << " " << *I2 << "\n";); // We need to update RE1 and RE2 if we are going to sink the first // instruction in the basic block down. bool UpdateRE1 = (I1 == BB1->begin()), UpdateRE2 = (I2 == BB2->begin()); @@ -1489,7 +1467,8 @@ static Value *isSafeToSpeculateStore(Instruction *I, BasicBlock *BrBB, /// /// \returns true if the conditional block is removed. static bool SpeculativelyExecuteBB(BranchInst *BI, BasicBlock *ThenBB, - const DataLayout *DL) { + const DataLayout *DL, + const TargetTransformInfo &TTI) { // Be conservative for now. FP select instruction can often be expensive. Value *BrCond = BI->getCondition(); if (isa<FCmpInst>(BrCond)) @@ -1538,7 +1517,8 @@ static bool SpeculativelyExecuteBB(BranchInst *BI, BasicBlock *ThenBB, EndBB)))) return false; if (!SpeculatedStoreValue && - ComputeSpeculationCost(I, DL) > PHINodeFoldingThreshold) + ComputeSpeculationCost(I, DL, TTI) > PHINodeFoldingThreshold * + TargetTransformInfo::TCC_Basic) return false; // Store the store speculation candidate. @@ -1597,9 +1577,11 @@ static bool SpeculativelyExecuteBB(BranchInst *BI, BasicBlock *ThenBB, if ((ThenCE && !isSafeToSpeculativelyExecute(ThenCE, DL)) || (OrigCE && !isSafeToSpeculativelyExecute(OrigCE, DL))) return false; - unsigned OrigCost = OrigCE ? ComputeSpeculationCost(OrigCE, DL) : 0; - unsigned ThenCost = ThenCE ? ComputeSpeculationCost(ThenCE, DL) : 0; - if (OrigCost + ThenCost > 2 * PHINodeFoldingThreshold) + unsigned OrigCost = OrigCE ? ComputeSpeculationCost(OrigCE, DL, TTI) : 0; + unsigned ThenCost = ThenCE ? ComputeSpeculationCost(ThenCE, DL, TTI) : 0; + unsigned MaxCost = 2 * PHINodeFoldingThreshold * + TargetTransformInfo::TCC_Basic; + if (OrigCost + ThenCost > MaxCost) return false; // Account for the cost of an unfolded ConstantExpr which could end up @@ -1804,7 +1786,8 @@ static bool FoldCondBranchOnPHI(BranchInst *BI, const DataLayout *DL) { /// FoldTwoEntryPHINode - Given a BB that starts with the specified two-entry /// PHI node, see if we can eliminate it. -static bool FoldTwoEntryPHINode(PHINode *PN, const DataLayout *DL) { +static bool FoldTwoEntryPHINode(PHINode *PN, const DataLayout *DL, + const TargetTransformInfo &TTI) { // Ok, this is a two entry PHI node. Check to see if this is a simple "if // statement", which has a very simple dominance structure. Basically, we // are trying to find the condition that is being branched on, which @@ -1835,6 +1818,8 @@ static bool FoldTwoEntryPHINode(PHINode *PN, const DataLayout *DL) { SmallPtrSet<Instruction*, 4> AggressiveInsts; unsigned MaxCostVal0 = PHINodeFoldingThreshold, MaxCostVal1 = PHINodeFoldingThreshold; + MaxCostVal0 *= TargetTransformInfo::TCC_Basic; + MaxCostVal1 *= TargetTransformInfo::TCC_Basic; for (BasicBlock::iterator II = BB->begin(); isa<PHINode>(II);) { PHINode *PN = cast<PHINode>(II++); @@ -1845,9 +1830,9 @@ static bool FoldTwoEntryPHINode(PHINode *PN, const DataLayout *DL) { } if (!DominatesMergePoint(PN->getIncomingValue(0), BB, &AggressiveInsts, - MaxCostVal0, DL) || + MaxCostVal0, DL, TTI) || !DominatesMergePoint(PN->getIncomingValue(1), BB, &AggressiveInsts, - MaxCostVal1, DL)) + MaxCostVal1, DL, TTI)) return false; } @@ -2036,8 +2021,10 @@ static bool ExtractBranchMetadata(BranchInst *BI, "Looking for probabilities on unconditional branch?"); MDNode *ProfileData = BI->getMetadata(LLVMContext::MD_prof); if (!ProfileData || ProfileData->getNumOperands() != 3) return false; - ConstantInt *CITrue = dyn_cast<ConstantInt>(ProfileData->getOperand(1)); - ConstantInt *CIFalse = dyn_cast<ConstantInt>(ProfileData->getOperand(2)); + ConstantInt *CITrue = + mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(1)); + ConstantInt *CIFalse = + mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(2)); if (!CITrue || !CIFalse) return false; ProbTrue = CITrue->getValue().getZExtValue(); ProbFalse = CIFalse->getValue().getZExtValue(); @@ -2534,17 +2521,15 @@ static bool SimplifyCondBranchToCondBranch(BranchInst *PBI, BranchInst *BI) { // The weight to CommonDest should be PredCommon * SuccTotal + // PredOther * SuccCommon. // The weight to OtherDest should be PredOther * SuccOther. - SmallVector<uint64_t, 2> NewWeights; - NewWeights.push_back(PredCommon * (SuccCommon + SuccOther) + - PredOther * SuccCommon); - NewWeights.push_back(PredOther * SuccOther); + uint64_t NewWeights[2] = {PredCommon * (SuccCommon + SuccOther) + + PredOther * SuccCommon, + PredOther * SuccOther}; // Halve the weights if any of them cannot fit in an uint32_t FitWeights(NewWeights); - SmallVector<uint32_t, 2> MDWeights(NewWeights.begin(),NewWeights.end()); PBI->setMetadata(LLVMContext::MD_prof, - MDBuilder(BI->getContext()). - createBranchWeights(MDWeights)); + MDBuilder(BI->getContext()) + .createBranchWeights(NewWeights[0], NewWeights[1])); } // OtherDest may have phi nodes. If so, add an entry from PBI's @@ -2718,7 +2703,7 @@ static bool SimplifyIndirectBrOnSelect(IndirectBrInst *IBI, SelectInst *SI) { /// the PHI, merging the third icmp into the switch. static bool TryToSimplifyUncondBranchWithICmpInIt( ICmpInst *ICI, IRBuilder<> &Builder, const TargetTransformInfo &TTI, - unsigned BonusInstThreshold, const DataLayout *DL, AssumptionTracker *AT) { + unsigned BonusInstThreshold, const DataLayout *DL, AssumptionCache *AC) { BasicBlock *BB = ICI->getParent(); // If the block has any PHIs in it or the icmp has multiple uses, it is too @@ -2751,7 +2736,7 @@ static bool TryToSimplifyUncondBranchWithICmpInIt( ICI->eraseFromParent(); } // BB is now empty, so it is likely to simplify away. - return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AT) | true; + return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true; } // Ok, the block is reachable from the default dest. If the constant we're @@ -2767,7 +2752,7 @@ static bool TryToSimplifyUncondBranchWithICmpInIt( ICI->replaceAllUsesWith(V); ICI->eraseFromParent(); // BB is now empty, so it is likely to simplify away. - return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AT) | true; + return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true; } // The use of the icmp has to be in the 'end' block, by the only PHI node in @@ -2947,20 +2932,9 @@ bool SimplifyCFGOpt::SimplifyResume(ResumeInst *RI, IRBuilder<> &Builder) { return false; // Turn all invokes that unwind here into calls and delete the basic block. - bool InvokeRequiresTableEntry = false; - bool Changed = false; for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE;) { InvokeInst *II = cast<InvokeInst>((*PI++)->getTerminator()); - - if (II->hasFnAttr(Attribute::UWTable)) { - // Don't remove an `invoke' instruction if the ABI requires an entry into - // the table. - InvokeRequiresTableEntry = true; - continue; - } - SmallVector<Value*, 8> Args(II->op_begin(), II->op_end() - 3); - // Insert a call instruction before the invoke. CallInst *Call = CallInst::Create(II->getCalledValue(), Args, "", II); Call->takeName(II); @@ -2980,14 +2954,11 @@ bool SimplifyCFGOpt::SimplifyResume(ResumeInst *RI, IRBuilder<> &Builder) { // Finally, delete the invoke instruction! II->eraseFromParent(); - Changed = true; } - if (!InvokeRequiresTableEntry) - // The landingpad is now unreachable. Zap it. - BB->eraseFromParent(); - - return Changed; + // The landingpad is now unreachable. Zap it. + BB->eraseFromParent(); + return true; } bool SimplifyCFGOpt::SimplifyReturn(ReturnInst *RI, IRBuilder<> &Builder) { @@ -3018,7 +2989,7 @@ bool SimplifyCFGOpt::SimplifyReturn(ReturnInst *RI, IRBuilder<> &Builder) { } // If we eliminated all predecessors of the block, delete the block now. - if (pred_begin(BB) == pred_end(BB)) + if (pred_empty(BB)) // We know there are no successors, so just nuke the block. BB->eraseFromParent(); @@ -3119,55 +3090,6 @@ bool SimplifyCFGOpt::SimplifyUnreachable(UnreachableInst *UI) { --i; --e; Changed = true; } - // If the default value is unreachable, figure out the most popular - // destination and make it the default. - if (SI->getDefaultDest() == BB) { - std::map<BasicBlock*, std::pair<unsigned, unsigned> > Popularity; - for (SwitchInst::CaseIt i = SI->case_begin(), e = SI->case_end(); - i != e; ++i) { - std::pair<unsigned, unsigned> &entry = - Popularity[i.getCaseSuccessor()]; - if (entry.first == 0) { - entry.first = 1; - entry.second = i.getCaseIndex(); - } else { - entry.first++; - } - } - - // Find the most popular block. - unsigned MaxPop = 0; - unsigned MaxIndex = 0; - BasicBlock *MaxBlock = nullptr; - for (std::map<BasicBlock*, std::pair<unsigned, unsigned> >::iterator - I = Popularity.begin(), E = Popularity.end(); I != E; ++I) { - if (I->second.first > MaxPop || - (I->second.first == MaxPop && MaxIndex > I->second.second)) { - MaxPop = I->second.first; - MaxIndex = I->second.second; - MaxBlock = I->first; - } - } - if (MaxBlock) { - // Make this the new default, allowing us to delete any explicit - // edges to it. - SI->setDefaultDest(MaxBlock); - Changed = true; - - // If MaxBlock has phinodes in it, remove MaxPop-1 entries from - // it. - if (isa<PHINode>(MaxBlock->begin())) - for (unsigned i = 0; i != MaxPop-1; ++i) - MaxBlock->removePredecessor(SI->getParent()); - - for (SwitchInst::CaseIt i = SI->case_begin(), e = SI->case_end(); - i != e; ++i) - if (i.getCaseSuccessor() == MaxBlock) { - SI->removeCase(i); - --i; --e; - } - } - } } else if (InvokeInst *II = dyn_cast<InvokeInst>(TI)) { if (II->getUnwindDest() == BB) { // Convert the invoke to a call instruction. This would be a good @@ -3191,7 +3113,7 @@ bool SimplifyCFGOpt::SimplifyUnreachable(UnreachableInst *UI) { } // If this block is now dead, remove it. - if (pred_begin(BB) == pred_end(BB) && + if (pred_empty(BB) && BB != &BB->getParent()->getEntryBlock()) { // We know there are no successors, so just nuke the block. BB->eraseFromParent(); @@ -3201,70 +3123,122 @@ bool SimplifyCFGOpt::SimplifyUnreachable(UnreachableInst *UI) { return Changed; } -/// TurnSwitchRangeIntoICmp - Turns a switch with that contains only a -/// integer range comparison into a sub, an icmp and a branch. -static bool TurnSwitchRangeIntoICmp(SwitchInst *SI, IRBuilder<> &Builder) { - assert(SI->getNumCases() > 1 && "Degenerate switch?"); +static bool CasesAreContiguous(SmallVectorImpl<ConstantInt *> &Cases) { + assert(Cases.size() >= 1); - // Make sure all cases point to the same destination and gather the values. - SmallVector<ConstantInt *, 16> Cases; - SwitchInst::CaseIt I = SI->case_begin(); - Cases.push_back(I.getCaseValue()); - SwitchInst::CaseIt PrevI = I++; - for (SwitchInst::CaseIt E = SI->case_end(); I != E; PrevI = I++) { - if (PrevI.getCaseSuccessor() != I.getCaseSuccessor()) + array_pod_sort(Cases.begin(), Cases.end(), ConstantIntSortPredicate); + for (size_t I = 1, E = Cases.size(); I != E; ++I) { + if (Cases[I - 1]->getValue() != Cases[I]->getValue() + 1) return false; - Cases.push_back(I.getCaseValue()); } - assert(Cases.size() == SI->getNumCases() && "Not all cases gathered"); + return true; +} - // Sort the case values, then check if they form a range we can transform. - array_pod_sort(Cases.begin(), Cases.end(), ConstantIntSortPredicate); - for (unsigned I = 1, E = Cases.size(); I != E; ++I) { - if (Cases[I-1]->getValue() != Cases[I]->getValue()+1) - return false; +/// Turn a switch with two reachable destinations into an integer range +/// comparison and branch. +static bool TurnSwitchRangeIntoICmp(SwitchInst *SI, IRBuilder<> &Builder) { + assert(SI->getNumCases() > 1 && "Degenerate switch?"); + + bool HasDefault = + !isa<UnreachableInst>(SI->getDefaultDest()->getFirstNonPHIOrDbg()); + + // Partition the cases into two sets with different destinations. + BasicBlock *DestA = HasDefault ? SI->getDefaultDest() : nullptr; + BasicBlock *DestB = nullptr; + SmallVector <ConstantInt *, 16> CasesA; + SmallVector <ConstantInt *, 16> CasesB; + + for (SwitchInst::CaseIt I : SI->cases()) { + BasicBlock *Dest = I.getCaseSuccessor(); + if (!DestA) DestA = Dest; + if (Dest == DestA) { + CasesA.push_back(I.getCaseValue()); + continue; + } + if (!DestB) DestB = Dest; + if (Dest == DestB) { + CasesB.push_back(I.getCaseValue()); + continue; + } + return false; // More than two destinations. } - Constant *Offset = ConstantExpr::getNeg(Cases.back()); - Constant *NumCases = ConstantInt::get(Offset->getType(), SI->getNumCases()); + assert(DestA && DestB && "Single-destination switch should have been folded."); + assert(DestA != DestB); + assert(DestB != SI->getDefaultDest()); + assert(!CasesB.empty() && "There must be non-default cases."); + assert(!CasesA.empty() || HasDefault); + + // Figure out if one of the sets of cases form a contiguous range. + SmallVectorImpl<ConstantInt *> *ContiguousCases = nullptr; + BasicBlock *ContiguousDest = nullptr; + BasicBlock *OtherDest = nullptr; + if (!CasesA.empty() && CasesAreContiguous(CasesA)) { + ContiguousCases = &CasesA; + ContiguousDest = DestA; + OtherDest = DestB; + } else if (CasesAreContiguous(CasesB)) { + ContiguousCases = &CasesB; + ContiguousDest = DestB; + OtherDest = DestA; + } else + return false; + + // Start building the compare and branch. + + Constant *Offset = ConstantExpr::getNeg(ContiguousCases->back()); + Constant *NumCases = ConstantInt::get(Offset->getType(), ContiguousCases->size()); Value *Sub = SI->getCondition(); if (!Offset->isNullValue()) - Sub = Builder.CreateAdd(Sub, Offset, Sub->getName()+".off"); + Sub = Builder.CreateAdd(Sub, Offset, Sub->getName() + ".off"); + Value *Cmp; // If NumCases overflowed, then all possible values jump to the successor. - if (NumCases->isNullValue() && SI->getNumCases() != 0) + if (NumCases->isNullValue() && !ContiguousCases->empty()) Cmp = ConstantInt::getTrue(SI->getContext()); else Cmp = Builder.CreateICmpULT(Sub, NumCases, "switch"); - BranchInst *NewBI = Builder.CreateCondBr( - Cmp, SI->case_begin().getCaseSuccessor(), SI->getDefaultDest()); + BranchInst *NewBI = Builder.CreateCondBr(Cmp, ContiguousDest, OtherDest); // Update weight for the newly-created conditional branch. - SmallVector<uint64_t, 8> Weights; - bool HasWeights = HasBranchWeights(SI); - if (HasWeights) { + if (HasBranchWeights(SI)) { + SmallVector<uint64_t, 8> Weights; GetBranchWeights(SI, Weights); if (Weights.size() == 1 + SI->getNumCases()) { - // Combine all weights for the cases to be the true weight of NewBI. - // We assume that the sum of all weights for a Terminator can fit into 32 - // bits. - uint32_t NewTrueWeight = 0; - for (unsigned I = 1, E = Weights.size(); I != E; ++I) - NewTrueWeight += (uint32_t)Weights[I]; + uint64_t TrueWeight = 0; + uint64_t FalseWeight = 0; + for (size_t I = 0, E = Weights.size(); I != E; ++I) { + if (SI->getSuccessor(I) == ContiguousDest) + TrueWeight += Weights[I]; + else + FalseWeight += Weights[I]; + } + while (TrueWeight > UINT32_MAX || FalseWeight > UINT32_MAX) { + TrueWeight /= 2; + FalseWeight /= 2; + } NewBI->setMetadata(LLVMContext::MD_prof, - MDBuilder(SI->getContext()). - createBranchWeights(NewTrueWeight, - (uint32_t)Weights[0])); + MDBuilder(SI->getContext()).createBranchWeights( + (uint32_t)TrueWeight, (uint32_t)FalseWeight)); } } - // Prune obsolete incoming values off the successor's PHI nodes. - for (BasicBlock::iterator BBI = SI->case_begin().getCaseSuccessor()->begin(); - isa<PHINode>(BBI); ++BBI) { - for (unsigned I = 0, E = SI->getNumCases()-1; I != E; ++I) + // Prune obsolete incoming values off the successors' PHI nodes. + for (auto BBI = ContiguousDest->begin(); isa<PHINode>(BBI); ++BBI) { + unsigned PreviousEdges = ContiguousCases->size(); + if (ContiguousDest == SI->getDefaultDest()) ++PreviousEdges; + for (unsigned I = 0, E = PreviousEdges - 1; I != E; ++I) + cast<PHINode>(BBI)->removeIncomingValue(SI->getParent()); + } + for (auto BBI = OtherDest->begin(); isa<PHINode>(BBI); ++BBI) { + unsigned PreviousEdges = SI->getNumCases() - ContiguousCases->size(); + if (OtherDest == SI->getDefaultDest()) ++PreviousEdges; + for (unsigned I = 0, E = PreviousEdges - 1; I != E; ++I) cast<PHINode>(BBI)->removeIncomingValue(SI->getParent()); } + + // Drop the switch. SI->eraseFromParent(); return true; @@ -3273,11 +3247,11 @@ static bool TurnSwitchRangeIntoICmp(SwitchInst *SI, IRBuilder<> &Builder) { /// EliminateDeadSwitchCases - Compute masked bits for the condition of a switch /// and use it to remove dead cases. static bool EliminateDeadSwitchCases(SwitchInst *SI, const DataLayout *DL, - AssumptionTracker *AT) { + AssumptionCache *AC) { Value *Cond = SI->getCondition(); unsigned Bits = Cond->getType()->getIntegerBitWidth(); APInt KnownZero(Bits, 0), KnownOne(Bits, 0); - computeKnownBits(Cond, KnownZero, KnownOne, DL, 0, AT, SI); + computeKnownBits(Cond, KnownZero, KnownOne, DL, 0, AC, SI); // Gather dead cases. SmallVector<ConstantInt*, 8> DeadCases; @@ -3484,6 +3458,21 @@ GetCaseResults(SwitchInst *SI, continue; } else if (Constant *C = ConstantFold(I, ConstantPool, DL)) { // Instruction is side-effect free and constant. + + // If the instruction has uses outside this block or a phi node slot for + // the block, it is not safe to bypass the instruction since it would then + // no longer dominate all its uses. + for (auto &Use : I->uses()) { + User *User = Use.getUser(); + if (Instruction *I = dyn_cast<Instruction>(User)) + if (I->getParent() == CaseDest) + continue; + if (PHINode *Phi = dyn_cast<PHINode>(User)) + if (Phi->getIncomingBlock(Use) == CaseDest) + continue; + return false; + } + ConstantPool.insert(std::make_pair(I, C)); } else { break; @@ -3509,12 +3498,6 @@ GetCaseResults(SwitchInst *SI, if (!ConstVal) return false; - // Note: If the constant comes from constant-propagating the case value - // through the CaseDest basic block, it will be safe to remove the - // instructions in that block. They cannot be used (except in the phi nodes - // we visit) outside CaseDest, because that block does not dominate its - // successor. If it did, we would not be in this phi node. - // Be conservative about which kinds of constants we support. if (!ValidLookupTableConstant(ConstVal)) return false; @@ -3655,7 +3638,7 @@ static void RemoveSwitchAfterSelectConversion(SwitchInst *SI, PHINode *PHI, /// phi nodes in a common successor block with only two different /// constant values, replace the switch with select. static bool SwitchToSelect(SwitchInst *SI, IRBuilder<> &Builder, - const DataLayout *DL, AssumptionTracker *AT) { + const DataLayout *DL, AssumptionCache *AC) { Value *const Cond = SI->getCondition(); PHINode *PHI = nullptr; BasicBlock *CommonDest = nullptr; @@ -3982,6 +3965,89 @@ static bool ShouldBuildLookupTable(SwitchInst *SI, return SI->getNumCases() * 10 >= TableSize * 4; } +/// Try to reuse the switch table index compare. Following pattern: +/// \code +/// if (idx < tablesize) +/// r = table[idx]; // table does not contain default_value +/// else +/// r = default_value; +/// if (r != default_value) +/// ... +/// \endcode +/// Is optimized to: +/// \code +/// cond = idx < tablesize; +/// if (cond) +/// r = table[idx]; +/// else +/// r = default_value; +/// if (cond) +/// ... +/// \endcode +/// Jump threading will then eliminate the second if(cond). +static void reuseTableCompare(User *PhiUser, BasicBlock *PhiBlock, + BranchInst *RangeCheckBranch, Constant *DefaultValue, + const SmallVectorImpl<std::pair<ConstantInt*, Constant*> >& Values) { + + ICmpInst *CmpInst = dyn_cast<ICmpInst>(PhiUser); + if (!CmpInst) + return; + + // We require that the compare is in the same block as the phi so that jump + // threading can do its work afterwards. + if (CmpInst->getParent() != PhiBlock) + return; + + Constant *CmpOp1 = dyn_cast<Constant>(CmpInst->getOperand(1)); + if (!CmpOp1) + return; + + Value *RangeCmp = RangeCheckBranch->getCondition(); + Constant *TrueConst = ConstantInt::getTrue(RangeCmp->getType()); + Constant *FalseConst = ConstantInt::getFalse(RangeCmp->getType()); + + // Check if the compare with the default value is constant true or false. + Constant *DefaultConst = ConstantExpr::getICmp(CmpInst->getPredicate(), + DefaultValue, CmpOp1, true); + if (DefaultConst != TrueConst && DefaultConst != FalseConst) + return; + + // Check if the compare with the case values is distinct from the default + // compare result. + for (auto ValuePair : Values) { + Constant *CaseConst = ConstantExpr::getICmp(CmpInst->getPredicate(), + ValuePair.second, CmpOp1, true); + if (!CaseConst || CaseConst == DefaultConst) + return; + assert((CaseConst == TrueConst || CaseConst == FalseConst) && + "Expect true or false as compare result."); + } + + // Check if the branch instruction dominates the phi node. It's a simple + // dominance check, but sufficient for our needs. + // Although this check is invariant in the calling loops, it's better to do it + // at this late stage. Practically we do it at most once for a switch. + BasicBlock *BranchBlock = RangeCheckBranch->getParent(); + for (auto PI = pred_begin(PhiBlock), E = pred_end(PhiBlock); PI != E; ++PI) { + BasicBlock *Pred = *PI; + if (Pred != BranchBlock && Pred->getUniquePredecessor() != BranchBlock) + return; + } + + if (DefaultConst == FalseConst) { + // The compare yields the same result. We can replace it. + CmpInst->replaceAllUsesWith(RangeCmp); + ++NumTableCmpReuses; + } else { + // The compare yields the same result, just inverted. We can replace it. + Value *InvertedTableCmp = BinaryOperator::CreateXor(RangeCmp, + ConstantInt::get(RangeCmp->getType(), 1), "inverted.cmp", + RangeCheckBranch); + CmpInst->replaceAllUsesWith(InvertedTableCmp); + ++NumTableCmpReuses; + } +} + /// SwitchToLookupTable - If the switch is only used to initialize one or more /// phi nodes in a common successor block with different constant values, /// replace the switch with lookup tables. @@ -4058,11 +4124,8 @@ static bool SwitchToLookupTable(SwitchInst *SI, // If the table has holes, we need a constant result for the default case // or a bitmask that fits in a register. SmallVector<std::pair<PHINode*, Constant*>, 4> DefaultResultsList; - bool HasDefaultResults = false; - if (TableHasHoles) { - HasDefaultResults = GetCaseResults(SI, nullptr, SI->getDefaultDest(), + bool HasDefaultResults = GetCaseResults(SI, nullptr, SI->getDefaultDest(), &CommonDest, DefaultResultsList, DL); - } bool NeedMask = (TableHasHoles && !HasDefaultResults); if (NeedMask) { @@ -4102,21 +4165,24 @@ static bool SwitchToLookupTable(SwitchInst *SI, "It is impossible for a switch to have more entries than the max " "representable value of its input integer type's size."); - // If we have a fully covered lookup table, unconditionally branch to the - // lookup table BB. Otherwise, check if the condition value is within the case - // range. If it is so, branch to the new BB. Otherwise branch to SI's default - // destination. - const bool GeneratingCoveredLookupTable = MaxTableSize == TableSize; - if (GeneratingCoveredLookupTable) { + // If the default destination is unreachable, or if the lookup table covers + // all values of the conditional variable, branch directly to the lookup table + // BB. Otherwise, check that the condition is within the case range. + const bool DefaultIsReachable = + !isa<UnreachableInst>(SI->getDefaultDest()->getFirstNonPHIOrDbg()); + const bool GeneratingCoveredLookupTable = (MaxTableSize == TableSize); + BranchInst *RangeCheckBranch = nullptr; + + if (!DefaultIsReachable || GeneratingCoveredLookupTable) { Builder.CreateBr(LookupBB); // We cached PHINodes in PHIs, to avoid accessing deleted PHINodes later, // do not delete PHINodes here. SI->getDefaultDest()->removePredecessor(SI->getParent(), - true/*DontDeleteUselessPHIs*/); + /*DontDeleteUselessPHIs=*/true); } else { Value *Cmp = Builder.CreateICmpULT(TableIndex, ConstantInt::get( MinCaseVal->getType(), TableSize)); - Builder.CreateCondBr(Cmp, LookupBB, SI->getDefaultDest()); + RangeCheckBranch = Builder.CreateCondBr(Cmp, LookupBB, SI->getDefaultDest()); } // Populate the BB that does the lookups. @@ -4167,11 +4233,11 @@ static bool SwitchToLookupTable(SwitchInst *SI, bool ReturnedEarly = false; for (size_t I = 0, E = PHIs.size(); I != E; ++I) { PHINode *PHI = PHIs[I]; + const ResultListTy &ResultList = ResultLists[PHI]; // If using a bitmask, use any value to fill the lookup table holes. Constant *DV = NeedMask ? ResultLists[PHI][0].second : DefaultResults[PHI]; - SwitchLookupTable Table(Mod, TableSize, MinCaseVal, ResultLists[PHI], - DV, DL); + SwitchLookupTable Table(Mod, TableSize, MinCaseVal, ResultList, DV, DL); Value *Result = Table.BuildLookup(TableIndex, Builder); @@ -4184,6 +4250,16 @@ static bool SwitchToLookupTable(SwitchInst *SI, break; } + // Do a small peephole optimization: re-use the switch table compare if + // possible. + if (!TableHasHoles && HasDefaultResults && RangeCheckBranch) { + BasicBlock *PhiBlock = PHI->getParent(); + // Search for compare instructions which use the phi. + for (auto *User : PHI->users()) { + reuseTableCompare(User, PhiBlock, RangeCheckBranch, DV, ResultList); + } + } + PHI->addIncoming(Result, LookupBB); } @@ -4214,12 +4290,12 @@ bool SimplifyCFGOpt::SimplifySwitch(SwitchInst *SI, IRBuilder<> &Builder) { // see if that predecessor totally determines the outcome of this switch. if (BasicBlock *OnlyPred = BB->getSinglePredecessor()) if (SimplifyEqualityComparisonWithOnlyPredecessor(SI, OnlyPred, Builder)) - return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AT) | true; + return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true; Value *Cond = SI->getCondition(); if (SelectInst *Select = dyn_cast<SelectInst>(Cond)) if (SimplifySwitchOnSelect(SI, Select)) - return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AT) | true; + return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true; // If the block only contains the switch, see if we can fold the block // away into any preds. @@ -4229,25 +4305,25 @@ bool SimplifyCFGOpt::SimplifySwitch(SwitchInst *SI, IRBuilder<> &Builder) { ++BBI; if (SI == &*BBI) if (FoldValueComparisonIntoPredecessors(SI, Builder)) - return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AT) | true; + return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true; } // Try to transform the switch into an icmp and a branch. if (TurnSwitchRangeIntoICmp(SI, Builder)) - return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AT) | true; + return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true; // Remove unreachable cases. - if (EliminateDeadSwitchCases(SI, DL, AT)) - return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AT) | true; + if (EliminateDeadSwitchCases(SI, DL, AC)) + return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true; - if (SwitchToSelect(SI, Builder, DL, AT)) - return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AT) | true; + if (SwitchToSelect(SI, Builder, DL, AC)) + return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true; if (ForwardSwitchConditionToPHI(SI)) - return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AT) | true; + return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true; if (SwitchToLookupTable(SI, Builder, TTI, DL)) - return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AT) | true; + return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true; return false; } @@ -4284,7 +4360,7 @@ bool SimplifyCFGOpt::SimplifyIndirectBr(IndirectBrInst *IBI) { if (SelectInst *SI = dyn_cast<SelectInst>(IBI->getAddress())) { if (SimplifyIndirectBrOnSelect(IBI, SI)) - return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AT) | true; + return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true; } return Changed; } @@ -4309,7 +4385,7 @@ bool SimplifyCFGOpt::SimplifyUncondBranch(BranchInst *BI, IRBuilder<> &Builder){ ; if (I->isTerminator() && TryToSimplifyUncondBranchWithICmpInIt(ICI, Builder, TTI, - BonusInstThreshold, DL, AT)) + BonusInstThreshold, DL, AC)) return true; } @@ -4318,7 +4394,7 @@ bool SimplifyCFGOpt::SimplifyUncondBranch(BranchInst *BI, IRBuilder<> &Builder){ // predecessor and use logical operations to update the incoming value // for PHI nodes in common successor. if (FoldBranchToCommonDest(BI, DL, BonusInstThreshold)) - return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AT) | true; + return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true; return false; } @@ -4333,7 +4409,7 @@ bool SimplifyCFGOpt::SimplifyCondBranch(BranchInst *BI, IRBuilder<> &Builder) { // switch. if (BasicBlock *OnlyPred = BB->getSinglePredecessor()) if (SimplifyEqualityComparisonWithOnlyPredecessor(BI, OnlyPred, Builder)) - return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AT) | true; + return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true; // This block must be empty, except for the setcond inst, if it exists. // Ignore dbg intrinsics. @@ -4343,14 +4419,14 @@ bool SimplifyCFGOpt::SimplifyCondBranch(BranchInst *BI, IRBuilder<> &Builder) { ++I; if (&*I == BI) { if (FoldValueComparisonIntoPredecessors(BI, Builder)) - return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AT) | true; + return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true; } else if (&*I == cast<Instruction>(BI->getCondition())){ ++I; // Ignore dbg intrinsics. while (isa<DbgInfoIntrinsic>(I)) ++I; if (&*I == BI && FoldValueComparisonIntoPredecessors(BI, Builder)) - return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AT) | true; + return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true; } } @@ -4362,7 +4438,7 @@ bool SimplifyCFGOpt::SimplifyCondBranch(BranchInst *BI, IRBuilder<> &Builder) { // branches to us and one of our successors, fold the comparison into the // predecessor and use logical operations to pick the right destination. if (FoldBranchToCommonDest(BI, DL, BonusInstThreshold)) - return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AT) | true; + return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true; // We have a conditional branch to two blocks that are only reachable // from BI. We know that the condbr dominates the two blocks, so see if @@ -4370,16 +4446,16 @@ bool SimplifyCFGOpt::SimplifyCondBranch(BranchInst *BI, IRBuilder<> &Builder) { // can hoist it up to the branching block. if (BI->getSuccessor(0)->getSinglePredecessor()) { if (BI->getSuccessor(1)->getSinglePredecessor()) { - if (HoistThenElseCodeToIf(BI, DL)) - return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AT) | true; + if (HoistThenElseCodeToIf(BI, DL, TTI)) + return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true; } else { // If Successor #1 has multiple preds, we may be able to conditionally // execute Successor #0 if it branches to Successor #1. TerminatorInst *Succ0TI = BI->getSuccessor(0)->getTerminator(); if (Succ0TI->getNumSuccessors() == 1 && Succ0TI->getSuccessor(0) == BI->getSuccessor(1)) - if (SpeculativelyExecuteBB(BI, BI->getSuccessor(0), DL)) - return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AT) | true; + if (SpeculativelyExecuteBB(BI, BI->getSuccessor(0), DL, TTI)) + return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true; } } else if (BI->getSuccessor(1)->getSinglePredecessor()) { // If Successor #0 has multiple preds, we may be able to conditionally @@ -4387,8 +4463,8 @@ bool SimplifyCFGOpt::SimplifyCondBranch(BranchInst *BI, IRBuilder<> &Builder) { TerminatorInst *Succ1TI = BI->getSuccessor(1)->getTerminator(); if (Succ1TI->getNumSuccessors() == 1 && Succ1TI->getSuccessor(0) == BI->getSuccessor(0)) - if (SpeculativelyExecuteBB(BI, BI->getSuccessor(1), DL)) - return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AT) | true; + if (SpeculativelyExecuteBB(BI, BI->getSuccessor(1), DL, TTI)) + return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true; } // If this is a branch on a phi node in the current block, thread control @@ -4396,14 +4472,14 @@ bool SimplifyCFGOpt::SimplifyCondBranch(BranchInst *BI, IRBuilder<> &Builder) { if (PHINode *PN = dyn_cast<PHINode>(BI->getCondition())) if (PN->getParent() == BI->getParent()) if (FoldCondBranchOnPHI(BI, DL)) - return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AT) | true; + return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true; // Scan predecessor blocks for conditional branches. for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) if (BranchInst *PBI = dyn_cast<BranchInst>((*PI)->getTerminator())) if (PBI != BI && PBI->isConditional()) if (SimplifyCondBranchToCondBranch(PBI, BI)) - return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AT) | true; + return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true; return false; } @@ -4484,7 +4560,7 @@ bool SimplifyCFGOpt::run(BasicBlock *BB) { // Remove basic blocks that have no predecessors (except the entry block)... // or that just have themself as a predecessor. These are unreachable. - if ((pred_begin(BB) == pred_end(BB) && + if ((pred_empty(BB) && BB != &BB->getParent()->getEntryBlock()) || BB->getSinglePredecessor() == BB) { DEBUG(dbgs() << "Removing BB: \n" << *BB); @@ -4515,7 +4591,7 @@ bool SimplifyCFGOpt::run(BasicBlock *BB) { // eliminate it, do so now. if (PHINode *PN = dyn_cast<PHINode>(BB->begin())) if (PN->getNumIncomingValues() == 2) - Changed |= FoldTwoEntryPHINode(PN, DL); + Changed |= FoldTwoEntryPHINode(PN, DL, TTI); Builder.SetInsertPoint(BB->getTerminator()); if (BranchInst *BI = dyn_cast<BranchInst>(BB->getTerminator())) { @@ -4547,7 +4623,7 @@ bool SimplifyCFGOpt::run(BasicBlock *BB) { /// of the CFG. It returns true if a modification was made. /// bool llvm::SimplifyCFG(BasicBlock *BB, const TargetTransformInfo &TTI, - unsigned BonusInstThreshold, - const DataLayout *DL, AssumptionTracker *AT) { - return SimplifyCFGOpt(TTI, BonusInstThreshold, DL, AT).run(BB); + unsigned BonusInstThreshold, const DataLayout *DL, + AssumptionCache *AC) { + return SimplifyCFGOpt(TTI, BonusInstThreshold, DL, AC).run(BB); } |